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[Octave-bug-tracker] [bug #50820] pwelch incorrectly discards DC compone
From: |
Shri |
Subject: |
[Octave-bug-tracker] [bug #50820] pwelch incorrectly discards DC component |
Date: |
Mon, 17 Apr 2017 17:39:48 -0400 (EDT) |
User-agent: |
Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:52.0) Gecko/20100101 Firefox/52.0 |
URL:
<http://savannah.gnu.org/bugs/?50820>
Summary: pwelch incorrectly discards DC component
Project: GNU Octave
Submitted by: theillusiveman
Submitted on: Mon 17 Apr 2017 09:39:47 PM UTC
Category: Octave Forge Package
Severity: 3 - Normal
Priority: 5 - Normal
Item Group: Incorrect Result
Status: None
Assigned to: None
Originator Name:
Originator Email:
Open/Closed: Open
Discussion Lock: Any
Release: 4.2.1
Operating System: Any
_______________________________________________________
Details:
Current setup:
Windows 10, GNU Octave 4.2.1, Signal Package 1.3.2.
Procedure to replicate issue:
Generate any signal (or use existing one if desired) with a non-zero DC. Use
the pwelch() method using one second window, no overlap to get the power
spectrum. Observe the DC coefficient on the result.
What to expect?:
The DC term to be the actual average of the signal.
What happens?:
The DC term is zero.
Additional info:
I used the attached code to test for the issue. I generated a sinusoid with
some DC offset. As a comparison, I generated the same graph on MATLAB. MATLAB
has the correct DC term while Octave does not. See the attached graphs to
observe the results. The graph name *_ML.png was generated in MATLAB. This
shows the proper DC term. Octave does not.
_______________________________________________________
File Attachments:
-------------------------------------------------------
Date: Mon 17 Apr 2017 09:39:47 PM UTC Name: pwtest.m Size: 259B By:
theillusiveman
<http://savannah.gnu.org/bugs/download.php?file_id=40424>
-------------------------------------------------------
Date: Mon 17 Apr 2017 09:39:47 PM UTC Name: PW_Test_ML.png Size: 23kB By:
theillusiveman
<http://savannah.gnu.org/bugs/download.php?file_id=40425>
-------------------------------------------------------
Date: Mon 17 Apr 2017 09:39:47 PM UTC Name: PW_Test_Oct.png Size: 14kB By:
theillusiveman
<http://savannah.gnu.org/bugs/download.php?file_id=40426>
_______________________________________________________
Reply to this item at:
<http://savannah.gnu.org/bugs/?50820>
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